Slipsheet, divider sheet and method for making the same

ABSTRACT

The present invention provides a slipsheet and/or divider sheet and a method for making the same, the sheet having an imprint or an embossing that provides a raised planar surface. The raised planar surface preferably comprises a plurality of ridges, crowns or crests, which are preferably arranged in a pattern throughout an upper surface of the sheet. To make the sheet, a die can be etched to have protuberances or bumps, and the die is preferably pressed into a sheet of pliable thermoplastic material. The sheet thus made has a plurality of indentation formed by the protuberances or bumps on the die, and the sheet has a planar outer surface comprising a plurality of ridges, crowns and crests between the indentations.

CROSS REFERENCE TO RELATED APPLICATION

Priority is claimed to U.S. Provisional Patent Application Ser. No.60/489,820 filed by the inventor on Jul. 24, 2003, which is incorporatedby reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention pertains to the field of transporting goods as a load ona pallet, and, more particularly, to a slipsheet or divider sheet onwhich goods can be placed for transport.

2. Description of the Related Art

Goods, typically packaged in cartons or boxes, have for some time beenplaced on a pallet, which can be picked up by a fork-lift vehicle andmoved on and off of a truck for transport from one place to another,about a warehouse for storage, and within a plant or factory where thegoods are made or used. Wooden pallets are frequently used, whichcomprises a top platform for receiving and supporting the goods, abottom platform that can rest on a floor or support surface, and railsor spacers separating the top and bottom platforms arranged in a mannerso that the forks of a fork-lift vehicle can be received in the pallet.These wooden pallets are relatively expensive to purchase and require agreat deal of room when transporting goods in a truck. Wooden palletsfrequently require transport to a place where needed, and transportingempty wooden pallets is relatively expensive.

Cardboard and plastic slipsheets were developed as a space-saving devicefor supporting a load of goods. Slipsheets are much less expensive thanwooden pallets and comprise a thin sheet of material that otherwise hasthe approximate dimensions of a typical wooden pallet. U.S. Pat. No. Re.29,192, issued to Anderson et al., describes a slipsheet and a fork-liftand push-pull type truck, which is a fork-lift vehicle with an apparatusfor handling a slipsheet, which Anderson et al. refer to as a slippallet. Anderson et al. describe a slip pallet formed as a square orrectangular sheet of a synthetic resin of selected types of polyolefin.The sheet is proportioned to fit upon the forks or platen of a lifttruck. The slipsheet has tabs at each edge, which can be gripped whenthe platen is thrust underneath the sheet, or the sheet can be pulledupon or pushed off from the platen by a push-pull apparatus used tomodify a standard fork-lift vehicle. Anderson et al. describe their slippallet as ordinarily carrying loads of boxes formed as interlockinglayers, and an important feature of their slip pallet resides inproviding a sheet having a greater coefficient of friction at the uppersurface whereon the boxes are placed than at the undersurface, which iscontacted by the platen.

The slip pallet of Anderson et al requires the upper surface of the slippallet be textured or otherwise modified to increase the frictionalresistance between the upper surface and the box load upon it. (Column7, lines 39-42.) Anderson et al. found that the frictional resistancebetween the undersurface of the pallet and the platen could be minimizedif the plastic sheet were roughened to a slight degree. (Column 8, lines7-10.) Anderson et al. state that the textured surface of the plasticslip pallet can best be obtained when the web from which the pallets areformed is being manufactured. A standard manufacturing procedure forproducing a web is by extruding hot thermoplastic material into the webform and finishing the web by moving it through sizing and coolingrollers. (Column 8, lines 13-19.) Anderson et al. suggest that theirslip pallet can be made by roughening one of the finishing and coolingrollers about which the sheet moves, and a suitable method forroughening or texturing the finishing and cooling roller is bysandblasting the surface of the roller or by using other modes ofroughening. (See column 8, lines 26-33.) Anderson et al. wanted toassure a comparatively high coefficient of friction between the surfaceof the plastic pallet and the paper material of an ordinary cardboardbox and stated that a depth of approximately 60 micro-inches of surfaceroughness is satisfactory to achieve the high friction that theydesired.

SUMMARY OF THE INVENTION

The present invention comprises a slipsheet and/or divider sheet with animprinted surface. The imprinted surface has a projecting areacomprising an outer support surface and an inner surface. The imprintedsurface is planar and preferably comprises a planar web-like or net-likestructure or a plurality of discrete surfaces that lie in a plane forsupporting goods placed on the support surface.

One embodiment of the present invention comprises a sheet ofthermoplastic material having opposing planar surfaces with one of thesurfaces having an embedded pattern. The pattern preferably comprises afirst row of indentations spaced apart and a second row of indentationsspaced apart, and the indentations of the second row are aligned betweenthe indentations of the first row. The rows of indentations arepreferably repeated to form the embedded pattern.

Another embodiment of the present invention comprises a method forforming a slipsheet or divider sheet, preferably by forming a sheet ofplastic material having a planar surface with a certain area andreducing the area by forming indentations into the sheet of plasticmaterial through the planar surface. An undented portion remainsundisturbed, which provides a planar support surface. The methodpreferably further includes providing a die having protuberances, wherethe die is used to form indentations by the protuberances in the sheetof plastic material. The protuberances on the die are preferablyarranged in a pattern to imprint a pattern in the sheet of plasticmaterial. The die is preferably etched and/or engraved to haveindentations of a uniform depth so that a raised surface will be formedon a sheet of plastic material when the die is pressed into the plasticmaterial while it is pliable so as to leave an embossed, planar supportsurface on the sheet of plastic material. In one embodiment a rollerhaving indentations etched to a uniform depth provides a satisfactorydie that can be placed between two smooth rollers.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of an imprinted surface on a slipsheet or dividersheet according to the present invention.

FIG. 2 is a plan view of a surface on a slipsheet or divider sheetaccording to the present invention.

FIG. 3 is a plan view of a surface of a slipsheet or divider sheetaccording to the present invention.

FIG. 4 is a cross-section as seen along the lines 4-4 in FIG. 3.

FIG. 5 is a plan view of surface of a slipsheet or a divider sheetaccording to the present invention.

FIG. 6 is a cross-section as seen along the lines 6-6 in FIG. 5.

FIG. 7 is a plan view of a surface of a slipsheet or divider sheetaccording to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides a slipsheet or divider sheet having asupport surface for supporting goods, such as boxes, packages, or emptycontainers before filling in a filling operation at a plant or factory.The support surface has a low coefficient of friction provided by havinga raised, partial surface. The slipsheet/divider sheet has a fullprojecting surface comprising the support surface, which is raised, anda recessed surface. The projecting surface is the combined set ofsurfaces seen in a plan view. By having a raised support surface, thereis less engagement between the support surface of the slipsheet ordivider sheet and the goods placed on the slipsheet or divider sheet.The raised support surface preferably extends over a majority of theprojecting area and provides a planar surface for supporting goods.

With reference to FIG. 1, a portion of a slipsheet or divider sheet 10is shown in plan view according to the present invention. The plan viewis of a small section showing an actual embodiment of the presentinvention. The dimensions shown in FIG. 1 are for a piece of materialabout 3 inches by 4 inches out of a sheet of material that may beapproximately 3 feet by 4 feet or any suitable dimension for a slipsheetor divider sheet. The terms slipsheet and divider sheet are usedinterchangeably herein as the present invention includes each. Aslipsheet may be used for supporting, as a pallet, a load of finishedgoods, while a divider sheet may be used for dividing layers of emptycontainers before being filled with a product. A slipsheet is typicallymade from high density polyethylene, which can be a recycled material. Adivider sheet is typically made from polypropylene, which tends to bestiffer than high density polyethylene typically used for making aslipsheet. However, other materials of construction can be used formaking a slipsheet and/or divider sheet according to the presentinvention, such as other types of polyolefins, co-polymers, cardboard,non-thermoplastic polymeric materials, and wood-based products.

Slipsheet 10 has a support surface 12 and a recessed surface 14. Supportsurface 12 comprises ridges 16 formed in a continuous pattern betweenedges 18, 20, 22 and 24. Looking at the plan view in FIG. 1 of slipsheet10, one sees a projected area comprising raised support surface 12 andrecessed surface 14. Raised support surface 12 is comprised of ridges16.

Turning to FIG. 2, a portion of a slipsheet or divider sheet 40 is shownin plan view according to the present invention. Slipsheet 40 has atotal projected area comprising a raised planar support surface 42 and arecessed surface 44. Support surface 42 comprises a first set of ridges42 a running from the lower left to the upper right and a second set ofridges 42 b running from the upper left to the lower right. Lines 42 aand 42 b intersect to form a diamond-shaped pattern. Ridges 42 a and 42b extend upwardly from recessed surface 44 to an essentially uniformheight to provide support surface 42 with a planar surface. In thisembodiment, recessed surface 44 comprises a plurality of oval-shapedindentations 46. Indentations 46 can have any of a number of differentshapes such as oval, circle, triangle, square, rectangle, diamond,parallelogram, and polygon, as well as three-dimensional analogs ofthese two-dimensional shapes. Indentations 46 comprise a first row ofindentations 46 a spaced apart essentially equally. A second row ofindentations 46 b is adjacent to first row of indentations of 46 a.Indentations 46 b are spaced essentially equally apart and are alignedin the spaces between indentations 46 a. The first and second rows ofindentations 46 a and 46 b, respectively, are repeated to form apattern, which comprises recessed surface 44. Recessed surface 44includes a bottommost surface defined by each indentation 46 and asloped surface rising from the bottommost surface to the support surface42, which is an uppermost surface.

Support surface 42, which comprises ridges 42 a and 42 b surface forsupporting boxes, cartons, or empty containers before the emptycontainers are filled with products. Support surface 42 provides lesscontact area as compared to a slipsheet having a smooth continuoussurface. By having this reduced surface area, a lower coefficient offriction is provided between slipsheet 40 and items placed on slipsheet40 as compared to the coefficient of friction between those items and aslipsheet having a smooth continuous surface. Alternatively, slipsheet40 can be turned over so that support surface 42 is in contact with theplaten of a fork-lift truck. An imprinted surface can also be formed onan opposing side of slipsheet 40 so that both sides have an imprintedsurface.

While slipsheet 40 in FIG. 2 could represent a scaled drawing of onesurface of a slipsheet or divider sheet, the drawing in FIG. 2represents in this embodiment a small portion of a slipsheet withdimensions of about 3 inches by about 4 inches, while the full-sizedslipsheet may have dimensions of about 3 feet by about 4 feet. Thedimensions can be of any size desired. Slipsheet 40 is one embodiment ofthe present invention showing one possible actual size for theindentations.

A slipsheet or divider sheet according to the present invention can bemade by etching and/or engraving a sizing or rolling die to haveprotuberances and a recessed surface. A sheet or web of thermoplasticmaterial, such as polyethylene, recycled polyethylene, polypropylene,co-polymers of monomers for such polymers or other polyolefins, ispassed over, under or around the roller engraved to have theprotuberances and recessed surfaces. In one embodiment three rollers arearranged one above another with an engraved roller in the middle. Acontinuous sheet of plastic passes between the rollers from top tobottom. The rollers press the sheet to a desired thickness. While thethermoplastic material is still warm and pliable, the protuberances onthe engraved roller form indentations in the sheet of plastic, while therecessed surfaces on the engraved roller form raised surfaces on thesheet of thermoplastic material. Alternatively, the protuberances on theroller may dent the surface of an otherwise smooth sheet of materialwhile the recessed portion of the roller has no contact with the sheet.The sheet of thermoplastic material can be cut to a desired length,while the width is defined by the width of the equipment processing thethermoplastic material to form the sheet. The sheet thus formed has asupport surface formed by the recessed surface on the roller and arecessed surface formed by the protuberances on the roller.

A pattern can be etched and/or engraved in the roller, and a negativeimage of the pattern can be formed in the sheet of thermoplasticmaterial to make a slipsheet or divider sheet according to the presentinvention. The recesses engraved in the roller are preferably at auniform depth so as to provide a support surface on the slipsheet ordivider sheet that is a planar surface. In this manner, a slipsheet ordivider sheet can be made having a coefficient of friction of a desiredvalue for a particular application. The size of the indentations can bedetermined as appropriate for the particular application for which theslipsheet is designed.

An etched roller can be made by grinding a roller to a desireddimension; coating the roller with a photosensitive material; preparinga sheet to wrap around the roller that is a negative of the desiredimage to be placed on the roller; wrapping the negative around theroller; exposing the roller and negative to a high intensity ultravioletlight; removing the negative; etching the roller; and acid washing theroller. A flash chrome plating can be applied to the roller forimproving release of a plastic sheet from the roller, for improvingcorrosion resistance, and for providing a hardened surface. An engravedor etched roller satisfactory for practicing the present invention canbe obtained from a company operating under the service mark Mold-Tech®in Youngstown, Ohio.

A plate can be used as an alternative to the roller, where the plate isused to stamp a sheet of thermoplastic material, while the material isstill warm and pliable. Other methods can be used to form recesses inthe surface of a slipsheet, such as by etching or carving, but it isbelieved to be more cost effective to imprint the sheet while it isstill warm and pliable during its initial manufacture. These othermethods may be more applicable if a non-thermoplastic polymericmaterial, a paper or wood-based material or a metal material is used.

Turning now to FIG. 3, a slipsheet or divider sheet 60 is illustrated inplan view. Slipsheet 60 has a total projecting area comprising a supportsurface 62 and a recessed surface 64. Support surface 62 comprises ridgerows 62 a and ridge columns 62 b. Recessed surface 64 comprises indentedsurfaces 64 a and transition or intermediate surfaces 64 b. Transitionsurface 64 b provides a transition from a lowermost surface, which isindented surface 64 a, and an uppermost surface, which is supportsurface 62 comprising rows and columns 62 a and 62 b, respectively.

FIG. 4 is a cross-section of slipsheet 60 in FIG. 3 as seen along thelines 4-4. Slipsheet 60 in FIG. 3 has been cut through recessed surface64, showing lowermost indented surface 64 a. For simplicity, notransition surface 64 b is shown in FIG. 4, although such surfacesgenerally exist. Recessed surface 64 is made by cylindricalindentations, which would be made by cylindrical protuberances on a die.Slipsheet 60 has a lower surface 66 and a base 68, which is a continuoussheet of material. An imprinted pattern is formed in base 68. Slipsheet60 has a thickness t, which can be of any suitable measure, but istypically around {fraction (1/16)}th of an inch. The thickness t maytypically range between about one millimeter and about five millimeters,but can be of any desirable thickness.

With reference to FIG. 5, a slipsheet or divider sheet 80 is shown inplan view and has a support surface 82 and a recessed surface 84. FIG. 6is a cross-section of slipsheet 80 in FIG. 5 as seen along the line 6-6.Slipsheet 80 is made by a die having hexagon-shaped protuberances and auniformally flat recessed surface, which forms support surface 82 duringmanufacture of slipsheet 80. An indentation 86 is defined by a recessedsurface 84 a in row 88.

As can be seen in FIG. 6, row 88 and an adjacent row 88 a define avertical structure 90, such as a ridge, crown or crest. Vertical supportstructure 90 has an uppermost surface 90 a, which comprises a portion ofsupport surface 82. While surfaces 90 a and 82 can be made by a recessedsurface in a die, these surfaces can be made as a sheet is made on amanufacturing line and be left undisturbed as dents are made in thesheet.

FIG. 7 is a plan view of another embodiment of the present invention, aslipsheet 100 having a support surface 102 and a recessed surface 104.Triangular-shaped protuberances 106 rise above recessed surface 104.Each of the triangular-shaped protuberances 106 has an upper surface 106a. Each of the upper surfaces 106 a combine to form support surface 102.Slipsheet 100 can be formed using a die having triangular-shapedrecesses to form protuberances 106. Each of the recesses can be engravedto a uniform depth to provide the planar support surface 102. In theembodiment of the invention illustrated by slipsheet 100, a plurality ofdiscrete flat surfaces 106 a comprise planar support surface 102. Eachupper surface 106 a of each protuberance 106 works in a cooperativefashion to provide planar support surface 102. However, the embodimentsof the invention where indentations are made, leaving ridges, crowns orcrests cooperating to provide a planar support surface, are preferredbecause it is believed that in making slipsheet 100, the plasticmaterial may become stuck in recesses in the die that would be used tomake protuberances 106, resulting in a less than ideal support surface102.

An unexpected benefit of imprinting a slipsheet or divider sheet is thatthe slipsheet or divider sheet is made stronger by the imprinting orembossing process. Without being held to theory, it is believed thatwhen a sheet of thermoplastic material is processed through machines asa continuous web, the polymer molecules in the sheet tend to align inthe machine direction. With the polymer molecules thus aligned, there islittle bonding between parallel molecular chains, which results in alower tear strength in the cross-machine direction than in the machinedirection. It is believed that the aligned molecules in the machinedirection are more strongly bonded together than adjacent, essentiallyparallel molecular chains along the cross-machine direction.

By imprinting or embossing a slipsheet or divider sheet while thematerial is still warm and pliable, it is believed that adjacent,parallel chains of molecules are moved out of parallel alignment, whichallows additional molecular bonding in the cross-machine direction. Thisadditional bonding in the cross-machine direction due to physicalmovement of the polymer chains due to the imprinting or embossingprocess is believed to provide additional molecular bonding in thecross-machine direction because the otherwise aligned, parallelconfiguration of the polymer chains is disturbed. Some of the polymerchains (and portions of polymer chains) are believed to be moved into across-machine alignment so that not essentially all polymer chains arealigned along the machine direction.

A slipsheet or divider sheet made as described above with an imprintedor embossed pattern has a greater tear strength in the cross-machinedirection than such a sheet made using a roller that has beensandblasted. This is an unexpected benefit relative to the sheets madeusing a sandblasted roller.

In summary, a slipsheet or divider sheet according to the presentinvention can be described in a number of ways. The slipsheet/dividersheet typically includes a sheet of thermoplastic material, althoughother materials, such as cardboard, can be used. The sheet may haveopposing planar surfaces and preferably has at least one planar surfacethat is imprinted or embossed. As a divider sheet, the imprinted surfacehas a support surface for supporting goods, such as boxes, cartons orcontainers. As a slipsheet, the imprinted pattern can be turned downwardto provide a low-friction surface for the platen on a forklift, whilethe upper surface can be smooth to provide a relatively high-frictionsurface for supporting goods. Both of the opposing planar surfaces canbe imprinted, particularly for use as a divider sheet.

The imprinted surface may comprise the upper surface of a plurality ofprotuberances projecting from the slipsheet/divider sheet. Moretypically, the support surface comprises the upper surface of aplurality of ridges, crowns and crests. The ridges may be arranged inrows and columns, but any suitable configuration that provides animprinted surface is satisfactory. Generally, the ridge, crown and creststructures cover a majority of the projecting surface of at least oneside of a sheet of material and can be on both sides.

In one embodiment, ridges are arranged in parallel rows, and theparallel rows intersect each other to form a pattern. It may be adiamond-shaped pattern, and alternatively, a square-shaped orrectangular-shaped pattern may be suitable. Indentations are preferablyformed between rows and columns of ridges. The ridges may be oriented ata 90-degree angle from a row to a column, but the angle can be varied sothat rows and columns at right angles are not formed. In a preferredembodiment, the ridges are arranged to form a diamond-shaped pattern,but a pattern is not necessary. A uniform height or elevation of ridges,crowns and crests is desired to provide a planar support surface. Oneadvantage of the present invention is that the ridges, crowns and crestsprovide some rigidity to the sheet as compared to a sheet made using asandblasted roller. The ridges, crowns and crests appear to providestrengthening like corrugation does for a sheet of metal.

The present invention includes a method for forming a slipsheet ordivider sheet using a sheet of plastic material formed having a planarsurface with an area of x square units, reducing the planar surface to xminus y square units by forming indentations through the planar surface,and leaving a planar support surface. In one aspect, a slipsheet can beformed by pressing a sheet of plastic material with a device, such as aroller or press plate, having protuberances. The protuberances formindentations in the sheet and leave a plurality of raised surfaces thatform a support surface. The device may be engraved to have a pattern ofprotuberances and recessed surfaces, where the recessed surface on thedevice may form a raised surface on the sheet of plastic material. Asheet of plastic material is imprinted or embossed by pressing thedevice on the sheet. While one side of the sheet has an imprinted orembossed surface to provide a raised support surface, the opposing sideof the sheet is typically smooth, but may have an imprinted or embossedsurface of any desired type. The imprinted or embossed surface providesa support surface, and the support surface may comprise a continuousweb, grid-like or net-shaped structure or discrete and discontinuoussurfaces. The coefficient of friction on the support surface ispreferably less than the coefficient of friction on an opposing surface,which may typically be an underside of the slipsheet or divider sheet.

One application for the present invention is as a divider sheet,particularly for holding empty containers, such as cans or bottles, forfeeding the containers into an apparatus for filling or loading thecontainers. Divider sheets may be made using high density polyethylene(HDPE), polypropylene or any suitable material that, when imprinted,provides a relatively low coefficient of friction. An advantage of thelow coefficient of friction between the container and the divider sheetis that the container can be easily slid off of the divider sheet ontoan assembly line for filling or loading the container. The filled orloaded container can easily be slid back onto the divider sheet. Forsuitable containers, vertical layers of the containers can be separatedby divider sheets made according to the present invention. A palletizedload can be made by alternating layers of containers and divider sheets,wrapping the stack in a shrink-wrap material, banding the load together,or otherwise providing a unitary package that can be transported by aforklift. The unitary package is preferably placed on a slipsheetaccording to the present invention, but may be placed on a conventionalpallet. The forklift handling the load on a divider sheet typically hasa push-pull apparatus for handling divider sheets.

The slipsheet of the present invention can be used as a pallet. A methodof using a slipsheet/divider sheet according to the present invention isto place the imprinted surface upwards for supporting a load of emptycontainers as a divider sheet and to use a sheet with the imprintedsurface down as a slipsheet. With the imprinted surface down, afork-lift truck can more easily pull a load onto the platen or forks ofthe fork-lift truck because there is less friction between theplaten/forks and the slipsheet when the slipsheet has an imprintedsurface according to the present invention. The slipsheet can have animprinted surface on a downward-facing surface and a smooth surface onan upward-facing surface. The downward-facing imprinted surface presentsa lower coefficient of friction between the sheet and platen of afork-lift vehicle than would be present between a smooth surface and theplaten. A smooth, upward-facing surface provides a higher coefficient offriction than an imprinted surface, and thus more gripping capability orholding capability for the slipsheet to hold a load of goods, such asboxes, on the upward-facing support surface of the slipsheet. Thus, theslipsheet/divider sheet of the present invention can be flipped overdepending on its application as a slipsheet or as a divider sheet.

Both the slipsheet and the divider sheet can be provided with anupturned tab, which can be more easily grabbed by a push-pull typefork-lift vehicle. The sheet can be scored parallel to an edge in amanner to provide an upturned tab of an appropriate dimension. Tabs onmultiple edges can be provided if desired.

The slipsheet described above can be made using HDPE, including somerecycled HDPE. In one embodiment of a slipsheet, a layer of linear lowdensity polyethylene (LLDPE) is co-extruded on top of a layer of HDPE toprovide an anti-slip property. The HDPE layer contacts an etched rollerthat provides an imprinted surface while the LLDPE layer contactsrollers with smooth surfaces. The imprinted HDPE layer is placeddownward to provide a low-friction surface for the platen, and therelatively softer and smoother LLDPE surface is placed upward to providea relatively high-friction surface for goods placed on the slipsheet.

There are several ways in which HDPE and LLDPE can be co-extruded.Separate sheet extrusion dies can be placed one above the other withLLDPE extruded and fed to the upper one and HDPE extruded and fed to thelower one. A small roller brings the LLDPE sheet parallel and adjacentto the HDPE layer. Both layers are then passed through three rollersarranged horizontally one above another, where the center roller hasbeen etched to have recesses separated by ridges of the originalsurface. The lower and upper rollers are smooth. The LLDPE layercontacts the smooth rollers while the HDPE layer contacts the etchedroller. The layer of LLDPE is bonded to the layer of HDPE as the twolayers are squeezed together while passing between adjacent rollers. Therollers are spaced sufficiently from the HDPE sheet extrusion die toallow for the LLDPE layer to be placed adjacent to the HDPE layer. For asingle sheet from one sheet extrusion die, the rollers would typicallybe placed immediately adjacent to the sheet extrusion die, but in thisembodiment the rollers are instead spaced apart from the extrusion die.

A second co-extrusion alternative is to feed the LLDPE to a co-extrusionbox in a line between the HDPE extruder and a single sheet extrusiondie. A third co-extrusion alternative is to feed the LLDPE immediatelyupstream of a single sheet extrusion die, which also receives theextruded HDPE. In each alternative a two-layer sheet of thermoplasticmaterial is formed, where one layer comprises primarily LLDPE and theother layer comprises primarily HDPE. After the extrusion and imprintingoperations, the continuous sheet can be passed forward for printing andcutting operations. The continuous sheet can be cut into pallet-sizedlengths and stacked and banded for shipment to customers.

The foregoing disclosure and description of the preferred and variousembodiments of the invention is illustrative only. Some alternatives forthe various features have been expressly disclosed, but other variationsand alternatives can be used. Various changes may be made in the designimprinted or embossed on a sheet. The material of construction can bealtered as can be the thickness of the material and depth of theimprint. The process for making the slipsheet or divider sheet can bealtered in various ways. Uses and applications for the slipsheet anddivider sheet may encompass more than the specific embodiments disclosedherein. The scope of the invention should be determined by the followingclaims and not by the specific embodiments used to illustrate theinvention.

1. A slipsheet or divider sheet, comprising: a sheet of material havingopposing sides one and two, side one having an imprinted surface, theimprinted surface comprising a raised surface and a recessed surface,wherein the raised surface lies substantially in a plane.
 2. Theslipsheet or divider sheet of claim 1, wherein the raised surfacecomprises a substantial portion of the imprinted surface.
 3. Theslipsheet or divider sheet of claim 1, wherein the material isthermoplastic.
 4. The slipsheet or divider sheet of claim 1, wherein theraised surface comprises a set of discrete surfaces.
 5. The slipsheet ordivider sheet of claim 1, wherein the recessed surface comprises a setof discrete shapes.
 6. The slipsheet or divider sheet of claim 1,wherein the recessed surface comprises indentations that have a shapeselected from the group of shapes consisting of oval, circle, triangle,square, rectangle, diamond, parallelogram, and polygon.
 7. The slipsheetor divider sheet of claim 1, wherein an intermediate surface liesbetween the raised surface and the recessed surface, and wherein theintermediate surface and the raised surface form a continuous web-like,net-like or grid-like structure.
 8. The slipsheet or divider sheet ofclaim 1, wherein the raised surface comprises a plurality of ridges,crowns or crests.
 9. The slipsheet or divider sheet of claim 1, whereinside two has a relatively smooth surface.
 10. The slipsheet or dividersheet of claim 9, wherein side one comprises a layer of high densitypolyethylene and side two comprises a layer of linear low densitypolyethylene.
 11. A slipsheet or divider sheet, comprising: a sheet ofthermoplastic material having opposing planar surfaces, wherein at leastone of the planar surfaces has an embedded pattern, the patterncomprising a first row of indentations spaced apart; and a second row ofindentations spaced apart, wherein the indentations of the second roware between the indentations of the first row; and wherein the first andsecond rows are repeated to form the embedded pattern.
 12. The slipsheetor divider sheet of claim 11, wherein the indentations in the first andsecond rows are spaced approximately equally apart.
 13. The slipsheet ordivider sheet of claim 12, wherein the embedded pattern comprises rowsand columns of indentations, wherein the columns are spacedapproximately equally apart.
 14. The slipsheet or divider sheet of claim11, wherein the indentations have a shape selected from the group ofshapes consisting of oval, circle, triangle, square, rectangle, diamond,parallelogram, and polygon.
 15. The slipsheet or divider sheet of claim11, wherein a ridge is between the first and second rows ofindentations, and wherein the slipsheet has a plurality of ridges, eachridge having an upper surface, the upper surface of the ridges lyingsubstantially in a plane that forms a raised surface.
 16. The slipsheetor divider sheet of claim 15, wherein a crest is provided in each spacebetween indentations in a row, the crests each having an upper surfacethat lies substantially in the plane that forms the raised surface. 17.The slipsheet or divider sheet of claim 16, wherein the planar surfacehaving the embedded pattern comprises a layer of high densitypolyethylene, and wherein the opposing surface comprises a relativelysmooth layer of linear low density polyethylene.
 18. A method forforming a slipsheet or divider sheet, comprising the steps of: forming asheet of material having a planar surface, the planar surface having anarea of x square units; and reducing the planar surface to x minus ysquare units by forming indentations to a non-random depth in the sheetthrough the planar surface.
 19. A method for making a slipsheet,comprising the steps of: forming a first sheet comprising high densitypolyethylene; forming a second sheet comprising linear low densitypolyethylene; and passing the first and second sheets through a set ofrollers, wherein the set of rollers press the first and second sheetstogether and form a single unitary sheet, and wherein one of the rollershas a surface indented by an etching process, the indented surface ofthe roller imparting a raised surface on the single unitary sheet.
 20. Amethod for forming a slipsheet or divider sheet, comprising the stepsof: providing a die having indentations; and pressing the die on a sheetso that the indentations on the die form a raised surface on the sheet,wherein the indentations on the die are not made by sandblasting thedie.
 21. The method for forming a slipsheet or divider sheet of claim20, wherein the sheet has an imprinted side and an opposing side, andwherein the opposing side has a relatively smooth surface.
 22. Themethod for forming a slipsheet or divider sheet of claim 21, wherein thecoefficient of friction between an aluminum can and the imprinted sideis measurably less than the coefficient of friction between the can andthe opposing side.
 23. The method for forming a slipsheet or dividersheet of claim 20, wherein the die forms a web-like, net-like orgrid-like plurality of ridges on the sheet, and wherein the plurality ofridges has an upper surface that lies substantially in a plane.
 24. Themethod of claim 20, wherein the tear strength of the slipsheet ordivider sheet in the cross-machine direction is greater than the tearstrength in the cross-machine direction of a similar sheet made using adie that has been sandblasted.
 25. The method of claim 20, wherein thecoefficient of friction between an aluminum can and the raised surfaceon the sheet is measurably less than the coefficient of friction betweenthe can and a similar sheet made using a die that has been sandblasted.26. A method for using a slipsheet, comprising the steps of: providing athermoplastic slipsheet having opposing sides one and two, wherein sideone is relatively smooth, and wherein side two has an imprinted pattern;placing goods on side one; and using a fork lift vehicle with platensand a push-pull device to move the slipsheet and goods, wherein side twocontacts the platens.
 27. The method of claim 26, wherein side onecomprises a layer of linear low density polyethylene, and wherein sidetwo comprises a layer of high density polyethylene.
 28. The method ofclaim 26, wherein the imprinted pattern includes a web-like, net-like orgrid-like set of ridges, the ridges having an outermost surface, andwherein the outermost surface of the ridges lie substantially in aplane.
 29. A method for using a divider sheet, comprising the steps of:providing a first thermoplastic divider sheet having opposing sides oneand two, wherein side one has an imprinted pattern; placing emptycontainers on side one; placing a second divider sheet over the emptycontainers resting on the first divider sheet; and placing emptycontainers on the second divider sheet.